This case study is an examination of the process of cognitive-behavioral play therapy on 8-year old boy with obsessive symptoms in behavior and thinking. To conduct the study, psychological tests are conducted before and after the intervention to determine the maintaining cause of problem behaviors and to explore the changes. The treatment consisted of 42 sessions of cognitive-behavioral therapy, including techniques such as exposure, contingency management, affective expression and modulation, cognitive restructuring, psychoeducation. The child’s obsessive thinking and behaviors were found to have decreased to a low level, as seen by the results of the child’s behaviors in therapy, self-reports, and parents/teacher reports. This article contributes to present how cognitive-behavioral play therapy techniques can be applied to obsessive symptoms.